Hydrocarbon separations



United States Patent 3,517,081 HYDROCARBON SEPARATIONS Rodney D.Beckham, Bridgeton, George D. Davis, Creve Coeur, and Earle C. Makin,Jr., St. Louis, Mo., assignors to Monsanto Company, St. Louis, Mo., acorporation of Delaware No Drawing. Filed July 29, 1968, Ser. No.748,199 Int. Cl. C07c 107/00; (110g /02 U.S. Cl. 260677 18 ClaimsABSTRACT OF THE DISCLOSURE A process for the separation and recovery ofunsaturated aliphatic hydrocarbons from admixture with saturatedaliphatic hydrocarbons by means of selective complex formation usingcuprous fiuoroborate and cuprous fluorophosphate as the complexingagent.

BACKGROUND OF THE INVENTION The present invention relates to a processfor the separation, purification and recovery of certain hydrocarbons.More particularly, the present invention relates to a process for theseparation and recovery of unsaturated aliphatic hydrocarbons fromadmixture with saturated aliphatic hydrocarbons.

A separations problem which has required and received considerableattention is that of separating unsaturated aliphatic hydrocarbons suchas olefins from close boiling and diflicultly separable saturatedaliphatic hydrocarbons such as the paraffin and naphthene hydrocarbons.Many processes have been proposed for such separations includingliquid-liquid extraction, extractive distillation, selective adsorption,easy tropic distillation, as well as complex formation. With respect tothis latter technique as applied to the separation of unsaturatedaliphatic hydrocarbons from saturated aliphatic hydrocarbons, variouscomplexing agents have been described, including such salts as cuprouschloride. However, none of these have been found acceptable to present,primarily, as a result of poor selectivity and/or the enability torecover the olefin hydrocarbons from the resulting complexes.

It is an object of the present invention to provide a new and improvedprocess for the separation of hydrocarbons. It is another object of thepresent invention to provide a new and improved process for theseparation of unsaturated aliphatic hydrocarbons from saturatedaliphatic hydrocarbons. Another object of the present invention is toprovide a new and improved process for the separation of olefinhydrocarbons from paraflin and/or naphthene hydrocarbons. An additionalobject of the present invention is to provide a process for theseparation of unsaturated aliphatic hydrocarbons from admixture withsaturated aliphatic hydrocarbons by means of complex formation. Anotherobject of the present invention is to provide a process for theseparation of unsaturated aliphatic hydrocarbons from admixture withsaturated aliphatic hydrocarbons by selectively complexing theunsaturated aliphatic hydrocarbons from said mixture and a means forrecovering the complexed unsaturated aliphatic hydrocarbons fromdecomplex. Additional objects will become apparent from the followingdescription of the invention herein disclosed. a

SUMMARY OF THE INVENTION The present invention, which fulfills these andother objects, is a process for the separation of unsaturated aliphatichydrocarbons from admixture with saturated aliphatic hydrocarbons whichcomprises contacting such a mixture with a first complex which comprisesa cuprous salt selected from the group consisting of cuprousfluoroborate and cuprous fluorophosphate and a hydrocarbon selected fromthe group consisting of olefins, aromatic hydrocarbons and mixtures ofolefins and aromatic hydrocarbons, thereby forming a first extract phaseand a first raifinate phase, separating said first extract and saidfirst raflinate phase, and recovering from said extract phase ahydrocarbon fraction containing unsaturated aliphatic hydrocarbons in asubstantially higher weight ratio to saturated aliphatic hydrocarbonsthan the original feed mixture and recovering from said raffinate phasea hydrocarbon fraction containing saturated aliphatic hydrocarbons in asubstantially higher weight ratio to the unsaturated aliphatichydrocarbons than in the original feed mixture.

While recovery of the unsaturated aliphatic hydrocarbons from theextract phase may be accomplished by the use of vacuum, heat or thelike, usually it is preferred to displace such hydrocarbons from theextract by contacting said extract with unsaturated aliphatichydrocarbons of a molecular weight different from those in the extractor, in the alternative, with vinyl aromatic hydrocarbons. The amount ofsuch hydrocarbons used to displace unsaturated aliphatic hydrocarbonsfrom the extract phase is at least a molar equivalent.

By means of the process disclosed herein, olefin and/ or diolefinhydrocarbons may be separated from paraffin and/ or naphthenehydrocarbons.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further describethe present invention, particularly with respect to the preferredembodiments thereof, the following examples are presented.

EXAMPLE I A first complex was prepared by dispersing 63.5 grams ofpowdered metallic copper along with 137.5 grams of CuF -2H O in 644grams of toluene and then continuously introducing gaseous BF into thedispersed medium until all solids had solubilized. The reaction mass wasmaintained at a temperature of approximately 110 C. and continuouslyagitated throughout addition of the BF with continuous removal of thewater generated. Agitation was continued for a period of several minutesand the product cooled back to ambient temperatures (73-75" F.). Thisfirst complex was intimately contacted with a mixture of 80.5 grams ofn-dodecane and 14.5 grams of n-dodecane. Temperatures during thecontacting period were ambient temperatures. An extract and raffinatephase rapidly formed and/or separated. The following table presents theweight percent concentration of n-dodecane and n-dodecene in the extractand raffinate phases, the concentration being calculated on a toluene-CuBF free basis:

A first complex prepared as described in Example I was contacted with amixture of 2.54 grams (39.1% by weight) of hexene-l and 3.94 grams(60.9% by weight) of n-heptane. The amount of first complex employed wasapproximately 8.6 grams. An extract and rafilnate phase rapidly formedand were separated. On analysis, the rniX- ture of hexene-l andn-heptane in the extract phase, normalized to was found to have acomposition 67.8% by weight hexene-l and 32.1% by weight n-heptane. Theraffinate phase had a composition 85.9 weight percent n-heptane and 14.1weight percent heXene-l. The rafiinate phase contained 66.5 weightpercent of the toluene initially present in the first complex, theremainder being retained in the extract phase.

The extract obtained above was re-extracted with a noncomplexinghydrocarbon diluent or solvent, in this case n-pentane. With 8.3 gramsof the extract, 4.7 grams of n-pentane was intimately contacted. A newraffinate and extract phase formed and were separated. The new orreextracted extract phase was found to consist of 52.4% by weight CuBF12.7% by weight toluene, 0.8% by weight n-heptane, 27.8% by weighthexene-l and 6.3% by weight n-pentane. The new rafiinate phase consistedof 24.0% by weight toluene, 13.5% by weight n-heptane, 4.4% by weighthexene-l and 58.1% by weigth n-pentane. The weight percent hexene-l andn-heptane in the re-extracted extract, calculated on a toluene,n-pentane and CuBF free basis, is 97.2% by weight hexene-l and 2.8% byweight heptane or an increase in hexene-l percent concentration of148.6% over the initial concentration in the feed.

EXAMPLE III To demonstrate the recovery of olefins from the extractphase with an olefin hydrocarbon of a different molecular weight, thehexene-l containing re-extracted extract of Example II was intimatelycontacted with pentene-l at a temperature of 25 C. The amount ofpentene-l used was in a weight ratio of 2:1 to hexene-l in the extractphase. An extract and a raffinate phase formed and were separated. Theextract phase again contacted with pentene-l in a weight ratio of 2:1.Again, an extract and raffinate phase formed and were separated. Theanalysis of percent by weight of the two rafiinate phases and the finalextract phase are presented in the following table:

Component First raflinate Second rathnate Extract Pentenc-I. 43. 7 64. 130. 20 Hexene-l 31. 6 23. 8. 70 Heptanm- 1. 'Ioluene 23. 2 12. 9 2. 70CUBF4 58. 60

The 8.7% by weight hexene-l in the extract represented 27.4% by weightof the hexene initially present in the reextracted extract contactedwith the pentene-l. The mixture of hexene-l and n-heptane contained inthe first raffinate phase normalized to 100%, consisted of 95.5% byweight hexene-l and only 4.5% by weight n-heptane and a second rafiinatecontained no n-heptane.

EXAMPLE IV A first complex prepared as described in Example I wascontacted with a 50-50 mixture of hexene-l and cyclohexane. Thetemperature during the contacting period was approximately 25%. Anextract and rafiinate phase rapidly formed and were separated. Thefollowing table presents the weight percent concentration of hexene-land cyclohexane in the extract and rafiinate phases, the concentrationbeing calculated on a toluene-CuBF free basis:

Rallinate Extract Component Hexenc-1 cyclohexane EXAMPLE V To thecuprous fluorophosphate containing first complex prepared above, a 1:1by weight mixture of cyclopentene and cyclopentane is contacted at atemperature of approximately 25 C. and at autogenous pressure. Theweight ratio of cuprous fiuorophosphate in the first complex tocyclopentene in the hydrocarbon mixture is approximately 1.5: l. Extractand rafiinate phases form and are separated. The raffinate phase isfound to contain a substantially higher ratio of cyclopentane tocyclopentene than was present in the original feed mixture. The extractphase is found to contain a substantially higher ratio of cyclopenteneto cyclopentane than in the original feed mixture.

EXAMPLE VI To demonstrate operation of the process of the presentinvention as a continuously operating process, a hydrocarbon mixtureconsisting of percent by weight nhexane and 30 percent cis-hexene-2 iscontinuously separated in an extraction column having approximately 20perforated trays, each tray capable of operating at approximately 50percent theoretical tray efiiciency. A first complex is continuouslyintroduced onto the top of the 20th tray from the bottom of theextraction column. This first complex is one prepared as follows:powdered metallic copper and CuF -2H O are dispersed in toluene, theweight ratio of Cu to CuF -2H O to toluene being 1:22 to 1:1.9. GaseousBE is then passed through the mixture until it is completely in liquidphase. The reaction mass is mainttained at a temperature ofapproximately 110 C. and continuously agitated throughout addition ofthe BF with continuous removal of the water generated. The agitation iscontinued for several minutes beyond the period of BF addition and theproduct cooled to ambient tem peratures (7375 F.).

Concurrently with introduction of the first complex onto the top of theextraction column, the above-defined hydrocarbon feed mixture iscontinuously introduced into the column between the 10th and 11th trayand n-heptane is continuously introduced below the first tray. Thecolumn is operated at a temperature within the range of 70 to F. and atautogenous pressure. The weight ratio of first complex to feed mixtureto n-heptane is 1:1.3:0.5. A rafiinate, termed the first rafiinate iscontinuously taken overhead from the extraction column and an extract,termed the first extract is continuously taken from the bottom. Therafiinate contains n-hexane and cis-hexene-2 in a weight ratio of 69:1.The extract contains n-hexane and cis-hexene-2 in a weight ratio of 1:30and contains approximately 1.4 percent of the n-hexane present in theoriginal mixture and about 97 percent by weight of the cis-hexene-2present in such original mixture.

The extract from the extraction column is continuously introduced into asecond extraction column adjacent a top plate thereof. Heptene-2 iscontinuously introduced into the second extraction column adjacent thebottom thereof, the weight ratio of the extract from the firstextraction column to the heptene-2 being 1:1. This second extractioncolumn is operated at substantially the same temperatures and pressuresas the first column. A rafiinate, termed the second raffinate, iscontinuously taken overhead from the second extraction column and anextract, termed the second extract is continuously taken from thebottom. The second rafiinate contains n-hexane and cis-hexene-2 in aweight ratio of 1:28. The extract has the composition of 33.9 percent byweight CuBF 20.8 percent by weight toluene, 0.9 percent by weightcishexene-2 and 44.4 percent by weight heptene-2. The extract from thesecond extraction column is recycled back to the first extraction columnas a part of the first complex introduced therein.

The cuprous salts employed in forming the complexes used in carrying outthe process of the present invention are cuprous tetrafluoroborate andcuprous hexafluorophosphate. Generally, these are referred to as cuprousfluoroborate and cuprous fluorophosphate. Both of these salts arerelatively unstable and cannot be readily formed as the salt. As aresult, the usual practice is to form the salt in the presence of anorganic compound with which the salt will complex, thereby forming thesalt and the complex of the salt with the organic compound almostconcurrently. This complex is referred to herein as the first complex.

The organic compounds in which the cuprous salts may be formed and withwhich such salts are immediately complexed to form the first complex mayinclude any of a rather large number of such compounds. As willhereinafter be more fully discussed, the choice of organic compound isoften dictated by the particular hydrocarbons in the hydrocarbon mixtureto be separated. Generally, however, the organic compounds will bearomatic hydrocarbons. Such aromatic hydrocarbons may contain a singlearomatic ring or may contain two or more condensed aromatic rings. Inaddition, the aromatic hydrocarbons may have substituents to the ring ormay be condensed with one or more other ring structures which areparaffinic or olefinic in nature. Non-limiting examples of aromatichydrocarbons suitable for use in preparing the cuprous salt-containingfirst complexes of the present invention are benzene, toluene, thexylene, various other polymethylbenzenes, such as mesitylene, isodurene,tri-, pentaand hexamethylbenzenes, ethylbenzene and the variouspolyethylbenzenes, isopropylbenzene, propylben- Zene and the variouspolyisopropyl and polypropylbenzenes, the various butyl andpentylbenzenes and the like; substituted benzenes containing two or moredifferent substituents such as ethyltoluene, isopropyltoluene, andethylxylenes; naphthalene, the various methylnaphthalenes, andpolymethylnaphthalenes, ethylnaphthalene and the variouspolyethylnaphthalenes, the naphthalenes containing propyl, isopropyl,butyl, and pentyl substituents; the substituted naphthalenes containingtwo or more different substituents such as methylethylnaphthalene,methylpropylnaphthalenes, etc.; the various indanes such asmethylindanes, ethylindanes, isopropylindanes, etc.; thedihydronaphthalenes such as methyl, ethyl, propyl, and butyl substituteddihydronaphthalenes; the tetrahydronaphthalenes such as methyl, ethyl,propyl, and pentyl substituted tetrahydronaphthalenes and the like. Inthe preferred practice of the present invention, the aromatichydrocarbons most often employed as the organic compound in forming thecomplexes of the present invention are benzene, naphthalene, partiallyhydrogenated naphthalenes, and the various alkylbenzenes andalkylnaphthalenes having alkyl substituents of not more than four carbonatoms per substituent. Within this group of preferred aromatichydrocarbons are such compounds as benzene, ethylbenzene, toluene, thexylenes, naphthalene and the methylnaphthalenes, dihydronaphthalene, andtetrahydronaphthalene and the like. A particularly useful group ofaromatic hydrocarbons for use in forming the first complexes of thepresent invention is that including such compounds as toluene,ethylbenzene, ethyltoluene, xylenes and tetrahydronaphthalene.

The method of preparing the cuprous fluoroboratearomatic hydrocarboncomplexes which are used for the separation of hydrocarbon mixtures inaccordance with the present invention may be any of those methodsconventionally used. In U.S. Pat. 2,953,589, the preparation of cuprousfluoroborate-aromatic hydrocarbon complexes by the introduction ofpowdered copper, BF and anhydrous HF into benzene or other aromatichydrocarbons is disclosed. This method may be used for the purposes ofthe present invention. In addition, the cuprous fluoroborate-aromatichydrocarbon complex may be prepared by dispersing CuF -2H O and metalliccopper in an aromatic hydrocarbon and heating the reaction mixture whileintroducing gaseous BF into the dispersed medium. This method isdescribed in Journal of the American Chemical Society, vol. 74, p. 3702, 1952. This latter described method is preferred for the practice ofthe present invention. In addition to these two methods of preparing thecuprous fluoroborate-aromatic hydrocarbon complex, any other of themethods known to those skilled in the art may be used.

Preparation of the cuprous fluorophosphate-aromatic hydrocarbon complexmay be by any of those means known to those skilled in the art.Preferably, however, this complex is prepared in introducing anhydrousCuF metallic copper and phosphorous pentafiuoride into an aromatichydrocarbon medium and heating with agitation to an elevated temperaturein excess of 75 C. The cuprous fluorophosphate-aromatic hydrocarboncomplexes may on occasion be solid at room temperature and therefore,must be maintained at elevated temperatures for use in the process ofthe present invention or, in the alternative, be used along with asuitable solvent. It is believed that impurities in the system causethese solid complexes. In addition to the above method of preparing thecuprous fiuorophosphate-aromatic hydrocarbon complex, any other methodknown to the art may be used.

As mentioned above, as an alternative to elevated temperatures, it ispossible to use a solvent in the preparation of the cuprousfiuorophosphate containing first complex to prevent formation of solidcomplexes. Such solvents include a Wide range of organic compounds,particularly those compounds containing oxygen and/or sulfur. Ethers,ketones, sulfones, disulfides, thioethers, thioureas, nitro alkyls andaryls, trihydrocarbonyl phosphines, and the like, represent classes ofuseful solvent. While the particular solvent selected is primarily amatter of individual choice, it is somewhat preferred that the solventbe one selected from the group consisting of the alkyl and arylsulfones, particularly such compounds as sulfolane and the alkylsulfolanes.

In preparing the cuprous salt-organic compound first complexes for usein the separations processes disclosed herein, some care should beexercised in the selection of the organic compound to avoid use of anorganic compound which itself may be diflicultly separable fromhydrocarbons of the mixture to be separated. Each mole of the cuproussalt-organic compound first complexes formed in accordance with thepresent invention generally will contain at least two moles of organiccompound and one mole of the cuprous salt. Separation of hydrocarbonmixtures in accordance with the process disclosed herein, involves thedisplacement of one or more of the moles of organic compound from thefirst complex and substitution therein of unsaturated aliphatichydrocarbon components of the mixutre to be separated. Since themolecule of organic compound displaced by these unsaturated componentsgenerally mix freely with the components of the feed mixture which donot complex with the cuprous salt, the organic compound of the firstcomplex should be one which may be readily and simply separated from thecon-complexed hydrocarbons of the hydrocarbon mixture.

The amount of first complex employed in carrying out the separation ofunsaturated aliphatic hydrocarbons from saturated aliphatic hydrocarbonsin accordance with the process of the present invention may varyconsiderably. However, the amount most often used is such as to providea mole ratio of the cuprous salt (CuBF or CuPF to the unsaturatedaliphatic hydrocarbons in the mixture to be separated within the rangeof 0.25:1 to 2:1. Preferably, the amount will be such as to provide amole ratio of cuprous salt to available unsaturated aliphatichydrocarbons of 0.5:1 to 1:1.

It has been found particularly useful in carrying out the separationsprocess of the present invention to use a con-complexible hydrocarbondiluent or solvent to aid in the formation of extract and ratfinatephases and/or for further extraction of the extract phases to removefrom such phases hydrocarbons which are not complexed with the cuproussalt. The use of such non-complexible hydrocarbons as to further extractan extract phase is exemplified in the Example II above. In mostinstances, the noncomplexible hydrocarbon employed is an aliphatichydrocarbon of 3 to 15 carbon atoms. Non-limiting examples of suchhydrocarbons are propane, n-butane, n-pentane, n-hexane, n-heptane,n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane,isobutane, isopentanes, isoheptanes, isodecanes, isododecanes,isotridecane, cyclopentane, cyclohexane, methylcyclohexane,cycloheptane, and the like. Most often, the saturated aliphatichydrocarbons are paraffinic hydrocarbons and may be straight-chain orbranched-chain. The most useful saturated aliphatic hydrocarbons are theparafiinic hydrocarbons of 4 to 7 carbon atoms per molecule. Inselecting the particular non-complexible hydrocarbon diluent or solventto use as above described, care should be exercised to avoid selectingone which itself will be difificulty separable from components of theresulting rafilnate and extract phases.

In the event a non-complexible hydrocarbon is employed to aid in theformation of extract and raffinate phases and/or for further extractionof the extract phases, the amount used may vary widely. The actual amunt of such hydrocarbons used will depend to a large extent on theamount of hydrocarbons in the hydrocarbon mixture to be separated whichwill not complex with the cuprous salt and on the degree of separationdesired. Usually, however, about 0.5 to 10 volumes of the noncomplexiblehydrocarbon is used per volume of saturated aliphatic hydrocarbon in thefeed mixture which is to be separated.

The separations process of the present invention may be practiced over awide range of temperatures and pressures. Most often, however, theprocess is practiced at temperatures within the range of 0.195 C.,preferably within the range of 25 to 150 C. The pressures employed forpracticing the process of the present invention do not appear to becritical and may range from subatmospheric pressures to superatmosphericpressures. As a practical matter, it is usually desirable to operate ator near atmospheric pressure, the pressures ranging from as low as 50mm. Hg to as high as 250 p.s.i.g. and higher.

In accordance with the process of the present invention, unsaturatedaliphatic hydrocarbons are separated from saturated aliphatichydrocarbons. Such separations include the separation of olefinhydrocarbons from paraffin and/or naphthene hydrocarbons and theseparation of diolefin hydrocarbons from paraffin and/or naphthenehydrocarbons. The molecular weight range of hydrocarbons which may beseparated include close boiling and difficultly separable hydrocarbonsof from 2 to 25 carbon atoms and higher. Generally speaking, any mixtureof unsaturated and saturated aliphatic hydrocarbons which is liquid orliquefiable under the conditions of separation may be successfullyseparated in accordance with the present invention. Liquefiablehydrocarbons include those which may be liquefied at the elevatedtemperatures suitable for operating the separations process of thepresent invention or which are liquefiable by mutual solubility withother components of the system or by solvents inert to the separationsprocess. Such separations as the separation of pentene from pentanes,hexenes from hcxanes, propylene from propane, pentenes fromcyclopentane, hexenes from cyclohexane or methylcyclopentanes, dodecanefrom dodecene, and the like, may be carried out through the presentseparations process. In the preferred embodiment of the separationsprocess of the present invention, olefin hydrocarbons containing 2 to 20carbon atoms are separated from difiicultly separable paraifin and/ ornaphthene hydrocarbons.

While the unsaturated aliphatic hydrocarbons contained in the extractphase may be recovered therefrom by any means such as heat, reducedpressure, and the like, it is usually preferred to displace thesehydrocarbons from the extract phase by means of another hydrocarbon.Such other hydrocarbons useful in displacing the unsaturated aliphatichydrocarbons are vinyl aromatic hydrocarbons and other olefinhydrocarbons, generally of a molecular weight different from the olefinhydrocarbons in the extract phase. Such vinyl aromatic hydrocarbons asstyrene, alphamethylstyrene, vinyl toluene and the like are useful. Theolefin hydrocarbons useful include those having as high as 20 carbonatoms and higher, again generally being those that are liquid orliquefiable at slightly elevated temperatures or by the use of solventsinert to the system or by mutual solubility with the components of theextract phase. Usually, the olefin hydrocarbons employed are thosehaving less than 15 carbon atoms. In choosing the vinyl aromatichydrocarbon or olefin hydrocarbon, care should be used that thehydrocarbon selected is not one which will itself be difiicultlyseparable from other hydrocarbon components of the system.

What is claimed is:

1. A process for the separation of unsaturated aliphatic hydrocarbonsfrom admixture with saturated hydrocarbons, said process comprisingcontacting a mixture of saturated and unsaturated aliphatic hydrocarbonswith a first complex which comprises a complex of a cuprous saltselected from the group consisting of cuprous fluoroborate and cuprousfluorophosphate and a hydrocarbon selected from the group consisting ofaromatic hydrocarbons, olefin hydrocarbons of a molecular weightdifferent from those of the unsaturated aliphatic hydrocarbons withinsaid mixture, and combinations of such aromatic hydrocarbons and olefinhydrocarbons, thereby forming an extract phase and a raflinate phase,separating said extract and raffinate phases, recovering from saidextract phase a hydrocarbon fraction containing unsaturated aliphatichydrocarbons in a substantially higher weight ratio to saturatedhydrocarbons than in the original mixture, and recovering from saidrafiinate phase a hydrocarbon fraction containing saturated hydrocarbonsin a substantially higher weight ratio to the unsaturated aliphatichydrocarbons than in said original mixture.

2. The process of claim 1 wherein the cuprious salt is cuprousfluoroborate.

3. The process of claim 2 wherein the first complex comprises cuprousfluoroborate and an aromatic hydrocarbon.

4. The process of claim 3 wherein the aromatic hydrocarbon is selectedfrom the group consisting of benzene, naphthalene, partiallyhydrogenated naphthalenes, the alkyl substituted derivatives of thesewherein the alkyl substituents have no more than 4 carbon atoms persubstituent, and mixtures of these.

5. The process of claim 4 wherein the aromatic hydrocarbon is toluene.

6. The process of claim 1 wherein said mixture is contacted with saidfirst complex at a temperature within the range of O to C.

7. The process of claim 1 wherein said unsaturated aliphatichydrocarbons are olefin hydrocarbons and wherein said saturatedhydrocarbons are of the group consisting of parafiin hydrocarbons,naphthene hydrocarbons and mixtures thereof.

8. The process of claim 7 wherein said saturated and unsaturatedaliphatic hydrocarbons are those having 7. to 20 carbon atoms permolecule.

9. The process of claim 1 wherein said unsaturated aliphatichydrocarbons are recovered from said extract phase by contacting saidextract phase with vinyl aromatic hydrocarbons, said vinyl aromatichydrocarbons being in at least molar equivalent with the unsaturatedaliphatic hydrocarbons within said extract phase.

10. The process of claim 1 wherein said unsaturated aliphatichydrocarbons are recovered from said extract phase by contacting saidextract phase with at least a molar equivalent of an olefin hydrocarbonof a molecular weight different from that of the unsaturated aliphatichydrocarbons in said extract phase.

11. The process of claim 1 wherein said first extract is re-extractedwith a non-complexible hydrocarbon.

12. The process of claim 11 wherein said non-complexible hydrocarbon isa saturated hydrocarbon of 3 to carbon atoms.

v13. The process of claim 1 wherein said first complex is present in anamount such as to provide a mole ratio of cuprous salt to theunsaturated aliphatic hydrocarbons in said mixture of saturated andunsaturated ali- {phatic hydrocarbons within the range of 0.25:1 to 2:1.

14. The process of claim 1 wherein the unsaturated aliphatichydrocarbons are olefin hydrocarbons of no greater than carbon atoms permolecule.

15. The process of claim 1 wherein said first complex comprises cuprousfluoroborate, an aromatic hydrocarbon and an olefin hydrocarbon.

16. The process of claim 15 wherein the aromatic hydrocarbon is selectedfrom the group consisting of benzene, naphthalene, partiallyhydrogenated naphthalenes, the alkyl substituted derivatives of thesewherein the alkyl substituents have no more than 4 carbon atoms persubistituent, and mixtures of these.

17. The process of claim 15 wherein the olefin hydrocarbon is one having2 to 20 carbon atoms per molecule.

18. A process for the separation of unsaturated aliphatic hydrocarbonsfrom saturated hydrocarbons comprising introducing a mixture ofsaturated and unsaturated hydrocarbons into a first extraction columnintermediate the ends thereof, concurrently introducing adjacent to topof said extraction column a first complex comprising a cuprous saltselected from the group consisting of cuprous fiuoroborate and cuprousfluorophosphate and a hydrocarbon selected from the group consisting ofaromatic hydrocarbons, olefin hydrocarbons and mixtures of olefins andaromatic hydrocarbons, concurrently introducing into said extractioncolumn adjacent the bottom thereof a non-complexible hydrocarbon,removing overhead from said first extraction column a first raflinatecontaining a hydrocarbon fraction substantially richer in the saturatedhydrocarbons of said mixture than the original hydrocarbon mixture,removing from the bottom of said extraction column a first extractphase, introducing said first extract phase into a second extractioncolumn intermediate the ends thereof, concurrently .introducing ahydrocarbon selected from the group consisting of olefin hydrocarbons ofa molecular weight different from the unsaturated aliphatic hydrocarbonsin said mixture and vinyl aromatic hydrocarbons, said hydrocarbon beingintroduced into a quantity which is at least in molar equivalent to theunsaturated aliphatic hydrocarbons in said first extract phase,concurrently introducing non-complexible hydrocarbons into said secondextraction column, removing from the bottom of said second extractioncolumn a second extract phase at least a portion of which is recycled tosaid first extraction column as at least a portion of said firstcomplex, removing overhead from said second extraction column a secondraflinate phase containing a hydrocarbon fraction substantially richerin the unsaturated aliphatic hydrocarbons of said mixture than saidoriginal hydrocarbon mixture.

References Cited UNITED STATES PATENTS 3,427,362 2/ 1969 Beckham et a1.260674 2,953,589 9/ 1960 McCaulay 260-438 2,913,505 11/1959 Van Raay etal. 260-677 FOREIGN PATENTS 859,440 5/ 1956 Great Britain.

OTHER REFERENCES James C. Warf, Journal of American Chem. Soc., vol. 74,1952, Toluene-Soluble Copper and Silver Fluoroiborates.

DELBERT E. vGANTZ, Primary Examiner J. D. M. NELSON, Assistant ExaminerUS. Cl. X.R.

